This invention relates generally to a die-cushion oil pressure locking device having an oil cooler device which can be fallen down the temperature of oil which is used by the press machine during operation.
The conventional die-cushion oil pressure locking device Z using in the press machine shown in FIGS. 6 and 7 is only done by falling down the outer wall of the locking device Y or the wall of the separated oil tank X.
Also, the designers have no idea about the using oil cooler device because the performance of durability has low level (in those day, the pressure limit of the oil cooler device is 10 kg/cm.sup.2), and they had the recognition that it is not enough to cool it down of 20 to 40 litters inside the oil cooler device with one shot and the shot repeats from 6 to 8 times per minute. The air cooling device W including the ways to falling down the temperature of the wall of the oil tank X or the locking device Y needs 2,000 litters of oil so that they do not have enough performance, and their size become larger than that of the conventional one. In addition, vibration trouble comes out, and the load of the die-cushion wrinkle increases. Therefore, there was the trouble of the shortness of oil packing's life because the temperature of oil is above 60.degree. C. (the oil temperature to up to about 120.degree. C.).